Tyrosine-PET identifies GBM "recurrence" or "late false progression"

Diagnosing "false progression" of glioblastoma (GBM) is a difficult problem; Studies have shown that false progression may be caused by changes in the blood-brain barrier caused by radiation and chemotherapyThe hypoxia induced by radiation radiation promotes the expression of endothelial growth factors in the blood vessels, the adhesion of the blood vessels increases and promotes the dysfunction of the blood-brain barrierIt is generally believed that false progression occurs within 12 weeks of radiotherapy, however, false progression can also occur 12 weeks after radiotherapy, known as "late false progression"Because the performance of MRI is very similar to the progression of a real tumor, late progression can interfere with treatment decisions, leading to unnecessary surgical removal- Excerpted from the article(Ref: Klekamp JGregory.2017 Jul 1;81 (1):29-44doi: 10.1093/neuros/nyx049.:diagnosing "false progression" of glioblastoma (GBM) is a challenge; Studies have shown that false progression may be caused by changes in the blood-brain barrier caused by radiation and chemotherapyThe hypoxia induced by radiation radiation promotes the expression of endothelial growth factors in the blood vessels, the adhesion of the blood vessels increases and promotes the dysfunction of the blood-brain barrierIt is generally believed that false progression occurs within 12 weeks of radiotherapy, however, false progression can also occur 12 weeks after radiotherapy, known as "late false progression"Because the performance of MRI is very similar to the progression of a real tumor, late progression can interfere with treatment decisions, leading to unnecessary surgical removalTherefore, rapid and accurate monitoring of the occurrence of false progressist, is the key to the treatment of GBMStudies have shown that the application of radioactively labeled amino acids, such as O-(2-(18F) fluorine ethyl)-L-tyrosine ((18F) FET), is a distinction between real tumor progression and false progression induced by radiation chemotherapy, as tracers ingestion reflects tumor amino acid transport rather than inflammatory processesStudies carried out by Constantin Lapa of the Nuclear Medicine Department at the University Hospital of W?rzburg, Germany, confirmed the effect of tyrosine-PET (FET-PET) in identifying the progression of GBM's trueness and late dysplonyThis article was published online in April 2018 by J Neurol Neurosurg the retrospective study included 36 patients with pathological diagnosis of glioblastoma, and tyrosine-PET scans were performed when tumor progression or recurrence was suspected Patients received radiotherapy and tyrosine-PET scans were separated by more than 12 weeks When the researchers looked at the cross-sectional image of the tyrosine-PET scan, they chose the area of interest on the axis picture of the maximum intake of the tumor The first area consists of a 10mm diameter circle centered on the highest active region and can derive the maximum (SUVmax) and average (SUmeanV) standard intake values In the brain tissue area of the opposite hemisphere, select a 50mm diameter reference area containing white and gray matter The tumor intake value is then divided by the standard intake value of the reference area to calculate the maximum and average ratios (TBRmax and TBRmean) diagnosis of "true tumor progression" at 4 weeks after initial evaluation, if histopathological diagnosis is positive, clinical symptoms are aggravated, or if there is progression in follow-up MRI imaging When the results of histopathological examination are negative, the clinical condition of the patient remains stable within 6 months, or the lesions of the enhanced sequence stabilize or even subside when THE MRI is reviewed after 4 weeks, it can be diagnosed as "late false progression" there was a significant increase in TBRmean and TBRmax in patients with true tumor progression compared to patients with late-onset progression When the TBRmax threshold of 3.52 is the best distinction between true tumor progression and late false progression, the accuracy is 86%, sensitivity 89%, specific 75%, the under-curve area (AUC) 0.87 x 0.07 (95% CI, 0.73-1.0; p-0.002) The results of the TBRmean calculation are similar to that of AUC at 0.84 to 0.08 (95% CI, 0.69-0.99; p-0.004), 83% accuracy, 82% sensitivity, 87.5% specificity, and best cut-off value of 2.98 In , tyrosine-PET scans are an effective way to distinguish between the progression of GBM real tumors and the progressof late dyslecity It is less sensitive to artifacts than MRI, and clinicians are able to review the progress or change of brain tumors due to the high contrast between the tumor and normal brain tissue.